JP3943888B2

JP3943888B2 - Anchor introduction load detection method, apparatus and program

Info

Publication number: JP3943888B2
Application number: JP2001316014A
Authority: JP
Inventors: 英信岡田; 邦保田中; 悟志草薙; 卓塚田; 孝之森; 渡大橋
Original assignee: Kajima Corp; Shikoku Electric Power Co Inc; SE Corp
Current assignee: Kajima Corp; Shikoku Electric Power Co Inc; SE Corp
Priority date: 2001-10-12
Filing date: 2001-10-12
Publication date: 2007-07-11
Anticipated expiration: 2021-10-12
Also published as: JP2003121278A

Description

【０００１】
【産業上の利用分野】
本発明はアンカー導入荷重の検出方法及び装置並びにプログラムに関し、とくに下部を地盤に固定したアンカーの頭部端から余長だけ下方部位の地上構造物への係止・緊張により導入したアンカー導入荷重の大きさを検出する方法及び装置並びにプログラムに関する。
【０００２】
【従来の技術】
グラウンドアンカー工法は、地盤中に設置したアンカー体と地上構造物に取り付けたアンカー頭部とを引張材で連結してアンカー体の引き抜き抵抗により地上構造物の安定を図る工法であり、斜面の安定化、構造物の転倒・浮き上がり防止、仮設山留め・土留め等の土木建築分野において広く利用されている。
【０００３】
従来のグラウンドアンカー工法の施工手順の一例を図８により簡単に説明する。先ず、削孔機13によってケーシングパイプやドリルパイプ14を地盤１へ打ち込み、安定地盤1aに至るアンカー孔８を穿つ（同図（Ａ））。そのアンカー孔８内に注入ホース15を挿入してグラウト16を注入し、アンカー孔８の底部から削孔水をグラウト16で置換する（同図（Ｂ））。次に、アンカー体３が下端に固定された鋼線、綱索又は鋼棒等の引張材４からなるアンカー２（図９参照）をアンカー孔８内のグラウト16中の所定位置（定着対象位置）へ落とし込み（同図（Ｃ））、アンカー孔８の頂部に加圧ヘッド18を取付けてグラウト16を加圧注入する（同図（Ｄ））。グラウト16が十分な強度に固化した後、引張材４の上端に固定したアンカー頭部５に所定の緊張力を導入してアンカー２を地盤１に定着する。緊張力は引張材４によりアンカー体３に伝えられ、更に周囲のグラウト16、安定地盤1aへと伝わる。
【０００４】
図９は従来のグラウンドアンカー２の一例（SEEEタイプ）を示す。同図のアンカー２は、ネジ式スペーサ19が取り付け可能なアンカー体（下部マンション）３とネジ付きアンカー頭部（頭部マンション）５とをPC鋼より線製の引張材４で連結したものである。鋼より線の本数は、アンカー２の導入荷重に応じて選択できる。また図示例の引張材４は、充填材により防錆した後に例えばポリエチレン樹脂製の被覆材11に被覆し、更に定着長部は波形管等の定着体28に包み込み、自由長部はスライドパイプ29に包み込む。同図のアンカー２は、グラウト16が固化したのち、アンカー頭部５のネジにナット６を螺合させて地上構造物７に締め付けることにより地盤１に定着する。ナット６による係止は、係止・緊張時の導入荷重を確実に計画荷重に合わせることができ、また再荷重が容易に可能である。アンカー頭部５のナット６から突出した余長部（頭部マンションの出代）5aは、風雨に侵されないようにアンカーキャップ９により保護する。図中の符号10は、ナット６の座金となるアンカープレートを示す。
【０００５】
グラウンドアンカー工法では、アンカー２の定着後の管理として、アンカー２に導入した荷重の経時的変化、すなわちアンカー２に所定の荷重が導入されているか否かを計測管理することが求められる。従来のアンカー導入荷重の計測管理では、図１０に示すように、アンカー２の頭部５に荷重検出器（ロードセル）21付き油圧ジャッキ20を取り付け、アンカー２に実際に引張荷重を加えてナット６と地上構造物７との間に荷重検出器21を取り付けることによりアンカーの導入荷重を計測・確認している。図示例では、不動梁24に取り付けた変位計23によってアンカー頭部５の変位を計測し、荷重と伸びとの関係（伸びが生じた時の荷重）からグラウンドアンカーの導入荷重を得る。図中の符号22は、油圧ジャッキ20とアンカー頭部５とを接続するカップラーを示す。
【０００６】
【発明が解決しようとする課題】
しかし、図１０に示す従来のアンカー導入荷重の計測管理方法は、大掛かりな測定装置を必要とし、現場での段取りや操作に時間がかかる問題点がある。また、アンカー２に実際に引張荷重を加えるので安全上好ましくない問題点もある。アンカー２の計測管理の容易化及び安全性向上を図るため、簡便な非破壊検査によりアンカー２の導入荷重を検出できる技術の開発が望まれている。
【０００７】
そこで本発明の目的は、アンカーの導入荷重を簡便な非破壊検査により検出する方法及び装置を提供することにある。
【０００８】
【課題を解決するための手段】
本発明者は、アンカー頭部５の余長部5aをハンマー等で打撃した時に生じるアンカーの振動周波数Ｆに注目し、アンカーの導入荷重Ｇと振動周波数Ｆとの関係を求める実験研究の結果、アンカー頭部５の余長長さL0が一定であれば導入荷重Ｇの増加に応じて振動周波数Ｆが大きくなる傾向があること、及び導入荷重Ｇが一定であれば余長長さL0の増加に応じて振動周波数Ｆが小さくなる傾向があることを実験的に見出した。すなわち、図９に示すような頭部５を有する既設アンカー２では、予め余長長さL0と振動周波数Ｆと導入荷重Ｇとの関係を求めておけば、既設アンカー２の余長長さL0と振動周波数Ｆとから導入荷重Ｇを推定できる。本発明は、この知見に基づく更なる実験研究の結果、完成に至ったものである。
【０００９】
図１のブロック図及び図２の流れ図を参照するに、本発明のアンカー導入荷重の検出方法は、下部を地盤１に固定したアンカー２の頭部５端から既知長さの余長L0だけ下方部位の地上構造物７への係止・緊張により導入したアンカー導入荷重Ｇを検出する方法において、既設アンカー２と同一の参照アンカー46（図４参照）を用いて前記既知長さのアンカー頭部５の余長部5aの打撃により余長部 5a に生じるアンカー46の振動周波数Ｆと導入荷重Ｇとの関係38（図６及び７参照）を実験的に求め、既設アンカー２の余長部5aの打撃によりアンカー頭部５の余長部 5a に生じる振動周波数Ｆを計測し、振動周波数Ｆの計測値と前記振動周波数Ｆ・導入荷重間Ｇの関係38とに基づき既設アンカー２の導入荷重Ｇを検出してなるものである。
【００１０】
好ましくは、振動周波数Ｆ・導入荷重Ｇ間の関係38を余長長さL0別に求め、既設アンカー２の余長長さL0を計測し、振動周波数Ｆ及び余長長さL0の計測値と前記振動周波数Ｆ・導入荷重Ｇ間の関係38とに基づき既設アンカー２の導入荷重Ｇを検出する。更に好ましくは、アンカー２、46の振動周波数Ｆを、該アンカー２、46の余長部5aの打撃により生じる振動振幅Ｖの経時変化のフーリエ変換により得られた複数の周波数成分Vfi（図５のVf1〜Vf6参照）のうちパワースペクトル量｜Vfi｜が最大の卓越成分の周波数Ｆ（図５の場合は成分Vf4の周波数F4）とする。
【００１１】
また図１のブロック図を参照するに、本発明のアンカー導入荷重の検出装置は、下部を地盤１に固定したアンカー２の頭部５端から既知長さの余長L0だけ下方部位の地上構造物７への係止・緊張により導入したアンカー導入荷重Ｇを検出する装置において、既設アンカー２の余長部5aの打撃によりアンカー頭部５の余長部 5a に生じる振動周波数Ｆを計測する周波数計32、既設アンカー２と同一の参照アンカー46（図４参照）の前記既知長さのアンカー頭部５の余長部5aの打撃により余長部 5a に生じる振動周波数Ｆと導入荷重Ｇとの関係38（図６及び７参照）を記憶する記憶手段37、及び周波数計32による振動周波数Ｆの計測値と前記振動周波数Ｆ・導入荷重Ｇ間の関係38とに基づき既設アンカー２の導入荷重Ｇを検出する荷重検出手段40を備えてなるものである。
【００１２】
また図２の流れ図を参照するに、本発明のアンカー導入荷重の検出プログラムは、下部を地盤１に固定したアンカー２の頭部５端から既知長さの余長L0だけ下方部位の地上構造物７への係止・緊張により導入したアンカー導入荷重Ｇを検出するためにコンピュータ36を、既設アンカー２と同一の参照アンカー46（図４参照）の前記既知長さのアンカー頭部５の余長部5aの打撃により余長部 5a に生じる振動周波数Ｆと導入荷重Ｇとの関係38（図６及び７参照）を記憶する記憶手段37、既設アンカー２の余長部5aの打撃によりアンカー頭部５の余長部 5a に生じる振動周波数Ｆを入力する入力手段42、及び振動周波数Ｆの入力値と前記振動周波数Ｆ・導入荷重Ｇ間の関係38とに基づき既設アンカー２の導入荷重Ｇを検出する荷重検出手段40として機能させるものである。
【００１３】
【発明の実施の形態】
図１は、本発明による導入荷重検出装置30の一実施例のブロック図を示す。図示例は、下部を地盤１に固定した既設アンカー２のネジ付き頭部５の上端から余長L0だけ下方部位をナット６により地上構造物７に締め付けて導入したアンカー導入荷重Ｇを検出する例を示す。但し、本発明の適用対象のアンカーは上端から余長L0だけ下方部位を地上構造物７に係止・緊張させるものであれば足り、その係止方法はネジ及びナットによる締め付けに限定されない。例えば、アンカー頭部５と地上構造物７とに設けた雌雄部材の嵌合により前記下方部位を地上構造物７に係止するアンカーにも本発明は適用可能である。
【００１４】
図１を参照するに、本発明の荷重検出装置30は、アンカー余長部5aの打撃時の振動周波数Ｆを計測する周波数計32と、記憶手段37と、荷重検出手段40とを有する。図示例の周波数計32は、アンカー余長部5aへ着脱自在に接続して余長部5aの打撃時に生じる振動振幅Ｖの経時変化を検知する振動センサ33と、振動振幅Ｖをフーリエ変換により図５に示すような複数の周波数成分Vfiに分解する信号変換手段34と、周波数成分Vfiのうちパワースペクトル量｜Vfi｜が最大の卓越成分の周波数Ｆをアンカー２の振動周波数Ｆとして求める卓越周波数検知手段35とを有する。
【００１５】
振動センサ33は、例えばアンカー余長部5aに生じた振動振幅Ｖの経時変化に応じてアナログ振動信号SVを出力する加速度センサである。信号変換手段34の一例は、振動センサ33の出力振動信号SVを入力してディジタル変換し、例えば高速フーリエ変換法（Fast Fourier Transform。以下、FFTという。）によって振動振幅Ｖを複数の周波数成分Vfiに分解するプログラムである。図５は信号変換装置34の出力結果の一例を表し、振動振幅Ｖが６つの周波数成分Vf1〜Vf6に分解された場合を示す。卓越周波数検知手段35は、信号変換装置34が出力した各周波数成分Vf1〜Vf6のパワースペクトル量｜Vfi｜を相互に比較し、パワースペクトル量｜Vfi｜が最大の卓越成分の周波数、例えば図５の場合は周波数成分Vf4の周波数F4を振動周波数Ｆとして出力するプログラムである。パワースペクトル量｜Vfi｜が最大の卓越成分の周波数Ｆは、特定の余長長さL0及び導入荷重Ｇという条件下におけるアンカー２の固有の振動周波数に相当する。信号変換手段34及び卓越周波数検知手段35の一例はFFTアナライザーであるが、これらを同図のコンピュータ36の内蔵プログラムである入力手段42に含めてもよい。なお、周波数成分Vfiが単純である場合は、卓越周波数検知手段35を省略して図５に示す信号変換装置34の出力波形から振動周波数Ｆを直接検知することも可能である。
【００１６】
荷重検出装置30の記憶手段37には、アンカー余長部5aの打撃による振動周波数Ｆとアンカー導入荷重Ｇとの関係38を実験的に求めて記憶する。また、荷重検出装置30の荷重検出手段40の一例は、周波数計32によるアンカーの振動周波数Ｆの計測値を入力手段42経由で入力し、記憶手段37に記憶した関係38を読み込み、振動周波数Ｆの計測値と関係38とに基づきアンカー導入荷重Ｇを検出するコンピュータ36に内蔵のプログラムである。
【００１７】
好ましくは、記憶手段37に振動周波数Ｆ・導入荷重Ｇ間の関係38を余長長さL0別に記憶し、アンカー２の頭部５の余長長さL0を計測する長さ計測器31を設け、荷重検出手段40により周波数計32による振動周波数Ｆの計測値と長さ計測器31による余長長さL0の計測値と前記余長長さL0別の振動周波数Ｆ・導入荷重Ｇ間の関係38とに基づき既設アンカー２の導入荷重Ｇを検出する。前記関係38を余長長さL0別に記憶しておくことにより、既設アンカー２の導入荷重Ｇをその余長長さL0に応じて検出することが可能となる。但し、既設アンカー２の余長長さL0が既知である場合は、その導入荷重Ｇの検出に際して既知の余長長さL0に対応する振動周波数Ｆ・導入荷重Ｇ間の関係38があれば足りるので、余長長さL0別の関係38や長さ計測器31は本発明に必須のものではない。
【００１８】
図２は、図１の検出装置30を用いて既設アンカー２の導入荷重を検出する方法の流れ図の一例を示す。以下、同流れ図を参照して本発明の導入荷重検出方法を説明する。先ずステップ201において、既設アンカー２と同一の参照アンカー46を用いて、アンカー余長部5aの打撃による振動周波数Ｆと導入荷重Ｇとの関係38を実験的に求める。例えば地盤に定着する前のアンカー２を参照アンカー46として用いることができる。
【００１９】
ステップ201の詳細を図３の流れ図に示す。図３のステップ301は、既設アンカー２と材質・構造・大きさ等が全て同一のアンカーにより、例えば図４に示すような参照アンカー46を製作することを示す。図４の参照アンカー46は、引張材４を反力壁47内に水平に貫通させ、アンカー頭部５を反力壁47の片側面に既設アンカー２の余長と同じ長さだけ突出させ、アンカー体３を反力壁47の反対側面に突出させてカップラー22により油圧ジャッキ48と結合したものである。突出させたアンカー頭部５は既設アンカー２と同一の方法、例えばナット６の締め付けにより反力壁47に取り付ける。油圧ジャッキ48がアンカー体３に加える水平外向き荷重がアンカー導入荷重Ｇに相当する。なお図４の符号49は、土嚢50を取り付けた作業安全用の鋼角ブロックを示す。
【００２０】
ステップ303において油圧ジャッキ48の荷重Ｇを計測し、ステップ304においてアンカー頭部５の余長部5aに図１の周波数計32のプローブ32aを接続し、余長部5aの打撃による振動周波数Ｆを周波数計32で計測する。更に油圧ジャッキ48の荷重Ｇを変えながら、ステップ303及び304を所要回数繰り返す（ステップ305）。ステップ303及び304で計測したジャッキ荷重Ｇと振動周波数Ｆの計測値をコンピュータへ入力し、コンピュータ36に内蔵のプログラムである関係検出手段41（図４参照）により図６（Ａ）に示すような振動周波数Ｆ・導入荷重Ｇ間の関係38のグラフを作成することができる。同グラフは余長長さL0を210mmで固定した場合の関係38を表し、余長長さL0が一定であれば導入荷重Ｇの増加に応じて振動周波数Ｆが大きくなることを示す。
【００２１】
好ましくは、参照アンカー46を用いて、異なる余長長さL0における振動周波数Ｆ・導入荷重Ｇ間の関係38のグラフを求める。この場合は、ステップ302においてアンカー頭部５の余長長さL0を図１の長さ計測器31で計測する。長さ計測器31の一例は、図９に示すナット６の座金からアンカー頭部５の上端までの距離を計測するスケール又は距離センサであるが、従来技術に属する他の適当な長さ計測器を用いることができる。長さ計測器31による余長長さL0の計測値は入力手段42を介してコンピュータ36に入力する。例えばナット６の締め付けの調節により余長長さL0を変えながらステップ302〜305を所要回数繰り返すことにより、余長長さL0別の振動周波数Ｆ・導入荷重Ｇ間の関係38のグラフを求めることができる（ステップ306）。
【００２２】
図６（Ｂ）及び（Ｃ）は、余長長さL0を230mm及び250mmとしたときの振動周波数Ｆ・導入荷重Ｇ間の関係38のグラフを示す。同グラフの作成に際し、ジャッキ荷重Ｇは同図（Ａ）のグラフ作成時と同様に変化させた。同図（Ａ）〜（Ｃ）の３グラフの比較から、導入荷重Ｇが一定であれば、余長長さL0の増加に応じて振動周波数Ｆが小さくなることが分かる。ステップ302〜306の繰り返しにより作成した関係38のグラフを、コンピュータ36の記憶手段37に記憶する（ステップ307）。
【００２３】
再び図２に戻り、ステップ201の終了後、計測管理の現地等において既設アンカー２の余長部5aの打撃時振動周波数Ｆを周波数計32により計測する（ステップ203）。また必要に応じて、既設アンカー２の余長長さL0を長さ計測器31により計測する（ステップ202）。ステップ204は、既設アンカー２の打撃時振動周波数Ｆ（及び、必要に応じて余長長さL0）の計測値を入力手段42経由で荷重検出手段40に入力し、記憶手段37に記憶した振動周波数Ｆ・導入荷重Ｇ間の関係38を荷重検出手段40に読み込み、荷重検手段40により振動周波数Ｆ（及び、必要に応じて余長長さL0）の入力値と関係38とに基づき既設アンカー２の導入荷重Ｇを検出する処理を示す。
【００２４】
具体的には、既設アンカー２の余長長さL0の入力値が210mm、230mm又は250mmであれば、振動周波数Ｆの入力値と実験的に求めた図６（Ａ）〜（Ｃ）の関係38のグラフとの交点を求めることにより既設アンカー２の導入荷重Ｇが検出できる。また、余長長さL0の入力値に対応する振動周波数Ｆ・導入荷重Ｇ間の関係38が実験的に求められていない場合であっても、関係38を余長長さL0別に求めてある場合は、後述するように余長長さL0及び振動周波数Ｆの入力値に応じた内挿法又は外挿法により、既設アンカー２の導入荷重Ｇを検出することが可能である。
【００２５】
図２のステップ205は、検出した既設アンカー２の導入荷重Ｇが正常であるか否かを判断する処理を示し、例えば所要の荷重が導入されていない場合はステップ206においてナット６の再緊張等の対策をとる。必要に応じて検出した導入荷重Ｇと判定結果とを記憶手段37に記憶し、ディスプレイ43aやプリンタ43bに出力することができる。但し、本発明はアンカー導入荷重Ｇを計測すれば足り、ステップ205〜206は本発明に必須のものではない。その後、他の既設アンカー２の導入荷重Ｇを計測する場合はステップ202へ戻り、上述したステップ202〜206を繰り返す（ステップ207）。既設アンカー２の材質・構造・大きさ等が全て同一である場合は、記憶手段36に記憶した振動周波数Ｆ・導入荷重Ｇ間の関係38を用いることができるので、ステップ201を繰り返す必要はない。
【００２６】
本発明の導入荷重検出装置30を可搬型とすることができ、ハンマー45等による打設という簡単な操作で既設アンカー２の導入荷重Ｇを検出できるので、従来技術のような大掛かりな測定装置や現場における煩雑な段取り・操作を不要とし、導入荷重Ｇの検出作業の簡単化及び迅速化が図れる。また、特別な熟練を必要とせず、誰でも容易に既設アンカー２の導入荷重Ｇが検出できる。しかも非破壊的検査であるため、安全上の問題を生じるおそれがない。
【００２７】
こうして本発明の目的である「アンカーの導入荷重を簡便な非破壊検査により検出する方法及び装置」の提供が達成される。
【００２８】
【実施例】
図３のステップ307では、図６に示すような余長長さL0別の振動周波数Ｆ・導入荷重Ｇ間の関係38を、例えば図７に示すように、二次元座標上に導入荷重Ｇ別に表わした余長長さL0と振動周波数Ｆとの関係の曲線群（以下、導入荷重検出用基準曲線39ということがある。）としている。振動周波数Ｆ・導入荷重Ｇ間の関係38を導入荷重検出用基準曲線39として表わすことにより、既設アンカー２の余長長さL0の計測値に対応する振動周波数Ｆ・導入荷重Ｇ間の関係を実験的に求めていない場合であっても、既設アンカー２の余長長さL0及び振動周波数Ｆの計測値を図７の二次元座標上にプロットすることにより、その余長長さL0及び振動周波数Ｆに対応する導入荷重Ｇを容易に検出できる。
【００２９】
図７に示す導入荷重検出用基準曲線39は、導入荷重Ｇを500kN、750kN及び1000kNとした場合の３本の曲線を含む。図７の二次元座標上にプロットした既設アンカー２の余長長さL0及び振動周波数Ｆの計測値座標が何れかの曲線と重なる場合は、アンカー導入荷重Ｇを直ちに検出できる。また、アンカー頭部５の余長長さL0が一定であれば導入荷重Ｇの増加に応じて振動周波数Ｆも増加するので、プロットした計測値座標が何れの曲線とも重ならない場合は、計測値座標を挟んで隣接する２本の曲線の導入荷重Ｇから既設アンカー２の導入荷重Ｇが推定できる。
【００３０】
具体的には、隣接する２本の曲線上で振動周波数Ｆ（又は余長長さL0）の計測値と対応する余長長さL0（又は振動周波数Ｆ）を求め、２本の曲線の導入荷重Ｇから余長長さL0（又は振動周波数Ｆ）の計測値に応じた内挿法又は外挿法により、既設アンカー２の導入荷重Ｇを検出する。導入荷重検出用基準曲線39には当然３本以上の曲線を含めることができ、各曲線の導入荷重Ｇの間隔を必要十分な大きさとすることにより既設アンカー２の導入荷重Ｇの検出精度を高めることが可能である。
【００３１】
【発明の効果】
以上説明したように、本発明のアンカー導入荷重の検出方法及び装置並びにプログラムは、既設アンカーの余長長さ及び余長部の打撃時の振動周波数を計測し、余長長さ及び振動周波数の計測値と実験的に求めた振動周波数・導入荷重間の関係とに基づき既設アンカーの導入荷重を検出するので、次の顕著な効果を奏する。
【００３２】
（イ）従来技術のような大掛かりな測定装置を必要とせず、可搬型の検出装置でアンカー導入荷重が検出できるので、計測管理作業の容易化が図れる。
（ロ）既設アンカーに検出装置を接続する等の簡単な操作で導入荷重が検出できるので、従来技術に比し計測管理作業の迅速化が図れる。
（ハ）検出作業に特別な熟練を必要としないので、誰でも容易に既設アンカーの導入荷重が検出できる。
（ニ）非破壊的検査であるため、安全上の問題を生じるおそれがない。
（ホ）振動周波数・導入荷重間の関係を実験的に十分整備すれば、アンカー導入荷重の高精度な検出が可能である。
（ヘ）コンピュータを用いてアンカー導入荷重が検出できるので、検出データの記録及び管理の容易化を図り、アンカーの記録管理上の人的誤りが防止できる。
（ト）アンカーの計測管理の自動化への寄与が期待できる。
【図面の簡単な説明】
【図１】は、本発明装置の一実施例のブロック図である。
【図２】は、本発明方法の流れ図の一例である。
【図３】は、振動周波数・導入荷重間の関係の作成方法の流れ図の一例である。
【図４】は、振動周波数・導入荷重間の関係を求める実験装置の説明図である。
【図５】は、振動周波数を求める方法の説明図である。
【図６】は、振動周波数・導入荷重間の関係を示すグラフの一例である。
【図７】は、振動周波数・導入荷重間の関係を示すグラフの他の一例である。
【図８】は、グラウンドアンカーの施工手順の説明図である。
【図９】は、従来のグラウンドアンカー構造の一例の説明図である。
【図１０】は、従来のアンカー導入荷重の検出方法の説明図である。
【符号の説明】
１…地盤 1a…安定地盤
２…アンカー３…アンカー体
４…引張材５…アンカー頭部
６…ナット７…地上構造物
８…アンカー孔９…アンカーキャップ
10…アンカープレート 11…被覆材
13…削孔機
14…ケーシングパイプ又はドリルパイプ
15…注入ホース 16…グラウト材
18…加圧ヘッド
19…スペーサ 20…油圧ジャッキ
21…ロードセル 22…カップラー
23…変位計 24…不動梁
25…変位計 26…不動梁
28…定着体 29…スライドパイプ
30…導入荷重検出装置 31…長さ計測器
32…周波数計 33…振動センサ
34…信号変換手段 35…卓越周波数抽出手段
36…コンピュータ 37…記憶手段
38…関数（関係のグラフ）
39…導入荷重検出用基準曲線
40…荷重検出手段 41…関係検出手段
42…入力手段 43a…ディスプレイ
43b…プリンタ 44…キーボード
45…ハンマー 46…参照アンカー
47…反力壁 48…油圧ジャッキ
49…鋼角ブロック 50…土嚢
Ｆ…振動周波数Ｇ…導入荷重
Ｖ…振動振幅 SV…アナログ振動信号
Vfi…周波数成分
｜Vfi｜…周波数成分のパワースペクトル量[0001]
[Industrial application fields]
The present invention relates to an anchor introduction load detection method, apparatus, and program, and more particularly, to an anchor introduction load introduced by locking / straining to the ground structure in a lower portion from the head end of the anchor with the lower portion fixed to the ground. The present invention relates to a method, an apparatus, and a program for detecting a size.
[0002]
[Prior art]
The ground anchor method is a method to stabilize the ground structure by connecting the anchor body installed in the ground and the anchor head attached to the ground structure with a tensile material, and pulling out the anchor body to stabilize the ground structure. It is widely used in the civil engineering and construction fields such as construction, prevention of falling and lifting of structures, temporary mountain retaining and earth retaining.
[0003]
An example of the construction procedure of the conventional ground anchor method will be briefly described with reference to FIG. First, a casing pipe or a drill pipe 14 is driven into the ground 1 by a drilling machine 13, and an anchor hole 8 reaching the stable ground 1a is drilled ((A) in the same figure). The injection hose 15 is inserted into the anchor hole 8 to inject the grout 16, and the drilling water is replaced with the grout 16 from the bottom of the anchor hole 8 ((B) in the figure). Next, an anchor 2 (see FIG. 9) made of a tensile material 4 such as a steel wire, a rope or a steel rod, to which the anchor body 3 is fixed at the lower end, is placed in a predetermined position (fixing target position) in the grout 16 in the anchor hole 8. The pressure head 18 is attached to the top of the anchor hole 8 and the grout 16 is pressure-injected (FIG. 4D). After the grout 16 has solidified to a sufficient strength, a predetermined tension is introduced into the anchor head 5 fixed to the upper end of the tension member 4 to fix the anchor 2 to the ground 1. The tension is transmitted to the anchor body 3 by the tension member 4 and further to the surrounding grout 16 and the stable ground 1a.
[0004]
FIG. 9 shows an example of a conventional ground anchor 2 (SEEE type). The anchor 2 in the figure is formed by connecting an anchor body (lower condominium) 3 to which a screw-type spacer 19 can be attached and a threaded anchor head (head condominium) 5 by a tensile material 4 made of PC steel wire. is there. The number of strands of steel can be selected according to the load introduced by the anchor 2. In the illustrated example, the tensile material 4 is rust-proofed with a filler, and then covered with a covering material 11 made of, for example, polyethylene resin. Wrap in. After the grout 16 is solidified, the anchor 2 shown in the figure is fixed to the ground 1 by screwing the nut 6 into the screw of the anchor head 5 and tightening it to the ground structure 7. Locking with the nut 6 can surely match the load introduced during locking and tensioning with the planned load, and can be easily re-loaded. The extra length portion 5a protruding from the nut 6 of the anchor head 5 is protected by an anchor cap 9 so as not to be affected by wind and rain. Reference numeral 10 in the drawing denotes an anchor plate that serves as a washer for the nut 6.
[0005]
In the ground anchor method, as management after anchor 2 is fixed, it is required to measure and manage a change with time of the load introduced into anchor 2, that is, whether or not a predetermined load is introduced into anchor 2. In the conventional measurement management of the anchor introduction load, as shown in FIG. 10, a hydraulic jack 20 with a load detector (load cell) 21 is attached to the head 5 of the anchor 2, and the nut 6 The load of the anchor is measured and confirmed by attaching a load detector 21 to the ground structure 7. In the illustrated example, the displacement of the anchor head 5 is measured by a displacement meter 23 attached to the stationary beam 24, and the introduction load of the ground anchor is obtained from the relationship between the load and the elongation (the load when the elongation occurs). Reference numeral 22 in the drawing denotes a coupler that connects the hydraulic jack 20 and the anchor head 5.
[0006]
[Problems to be solved by the invention]
However, the conventional anchor introduction load measurement and management method shown in FIG. 10 requires a large-scale measuring device, and has a problem that it takes time to set up and operate on site. Further, since a tensile load is actually applied to the anchor 2, there is also a problem that is not preferable for safety. In order to facilitate measurement management and improve safety of the anchor 2, it is desired to develop a technique that can detect the introduction load of the anchor 2 by a simple nondestructive inspection.
[0007]
Therefore, an object of the present invention is to provide a method and an apparatus for detecting the load of introducing an anchor by a simple nondestructive inspection.
[0008]
[Means for Solving the Problems]
The present inventor pays attention to the vibration frequency F of the anchor generated when the extra length portion 5a of the anchor head 5 is hit with a hammer or the like, and as a result of an experimental study for determining the relationship between the anchor introduction load G and the vibration frequency F, If the extra length L0 of the anchor head 5 is constant, the vibration frequency F tends to increase as the introduction load G increases, and if the introduction load G is constant, the extra length L0 increases. It has been found experimentally that the vibration frequency F tends to decrease according to the above. That is, in the existing anchor 2 having the head 5 as shown in FIG. 9, if the relationship between the extra length L0, the vibration frequency F and the introduction load G is obtained in advance, the extra length L0 of the existing anchor 2 is obtained. The introduction load G can be estimated from the vibration frequency F. The present invention has been completed as a result of further experimental studies based on this finding.
[0009]
Referring to the block diagram of FIG. 1 and the flowchart of FIG. 2, the anchor introduction load detection method of the present invention is lower than the head 5 end of the anchor 2 with the lower part fixed to the ground 1 by a surplus length L0 of a known length. In the method of detecting the anchor introduction load G introduced by locking / straining the part to the ground structure 7, the anchor head having the known length is used by using the same reference anchor 46 (see FIG. 4) as the existing anchor 2. relationship by blow elongated portion 5a of the 5 and the vibration frequency F of the anchor 46 that occurs elongated portion 5a and the introduction load G 38 (see FIGS. 6 and 7) determined experimentally, elongated portion 5a of the existing anchor 2 of I Ri measuring the vibration frequency F arising in elongated portion 5a of the anchor head 5 to blow the existing anchor 2 based on the relationship 38 of the measurement value and the vibration frequency F · introducing load between G vibration frequency F The introduction load G is detected.
[0010]
Preferably, the relationship 38 between the vibration frequency F and the introduction load G is obtained for each extra length L0, the extra length L0 of the existing anchor 2 is measured, and the measured values of the oscillation frequency F and the extra length L0 Based on the relationship 38 between the vibration frequency F and the introduction load G, the introduction load G of the existing anchor 2 is detected. More preferably, the vibration frequency F of the anchors 2 and 46 is converted into a plurality of frequency components Vfi (FIG. 5) obtained by Fourier transform of the change over time of the vibration amplitude V caused by the impact of the extra length portion 5a of the anchors 2 and 46. Vf1 to Vf6), the frequency F of the dominant component having the largest power spectrum amount | Vfi | (the frequency F4 of the component Vf4 in the case of FIG. 5).
[0011]
Referring also to the block diagram of FIG. 1, the anchor introduction load detecting device according to the present invention is the ground structure of the lower part of the lower part L0 of the known length from the end of the head 5 of the anchor 2 with the lower part fixed to the ground 1. an apparatus for detecting an anchor introduction load G introduced by the locking-tension to the object 7, the frequency of measuring the vibration frequency F generated in elongated portion 5a of the anchor head 5 by the striking of the elongated portion 5a of the existing anchor 2 meter 32, the known length of the vibration frequency F and introducing the load arising in due Ri excess length portion 5a to blow elongated portion 5a of the anchor head 5 of the existing anchors 2 and the same reference anchor 46 (see FIG. 4) The storage means 37 for storing the relationship 38 with G (see FIGS. 6 and 7), and the measured value of the vibration frequency F by the frequency meter 32 and the relationship 38 between the vibration frequency F and the introduced load G of the existing anchor 2 Load detecting means 40 for detecting the introduction load G is provided. Than it is.
[0012]
Referring to the flowchart of FIG. 2, the anchor introduction load detection program of the present invention is the above-mentioned ground structure at a lower portion of the head 5 of the anchor 2 with the lower part fixed to the ground 1 by a known length L0. In order to detect the anchor introduction load G introduced by the locking / straining to 7, the computer 36 is connected to the reference anchor 46 (see FIG. 4) identical to the existing anchor 2 and the extra length of the anchor head 5 of the known length. storage means 37 for storing the relationship 38 (see FIGS. 6 and 7) and the vibration frequency F arising in due Ri excess length portion 5a to the striking parts 5a and deployment load G, the blow elongated portion 5a of the existing anchor 2 The input means 42 for inputting the vibration frequency F generated in the extra length portion 5a of the anchor head 5 , and the introduction load of the existing anchor 2 based on the input value of the vibration frequency F and the relation 38 between the vibration frequency F and the introduction load G Function as load detecting means 40 for detecting G Than it is.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a block diagram of an embodiment of an introduction load detection device 30 according to the present invention. The illustrated example is an example of detecting an anchor introduction load G introduced by tightening a lower part to a ground structure 7 by a nut 6 from the upper end of a threaded head 5 of an existing anchor 2 whose lower part is fixed to the ground 1 with a nut 6. Indicates. However, the anchor to which the present invention is applied only needs to lock and tension the lower part of the ground structure 7 from the upper end by the extra length L0, and the locking method is not limited to tightening with screws and nuts. For example, the present invention is also applicable to an anchor that locks the lower portion to the ground structure 7 by fitting male and female members provided on the anchor head 5 and the ground structure 7.
[0014]
Referring to FIG. 1, the load detection device 30 of the present invention includes a frequency meter 32 that measures a vibration frequency F at the time of striking the anchor extra length portion 5a, a storage unit 37, and a load detection unit 40. The frequency meter 32 of the illustrated example is detachably connected to the anchor surplus length portion 5a and detects a vibration sensor 33 that detects a change with time of the vibration amplitude V generated when the surplus length portion 5a is struck. Signal conversion means 34 that decomposes into a plurality of frequency components Vfi as shown in FIG. 5, and a dominant frequency detection that finds the frequency F of the dominant component having the maximum power spectral quantity | Vfi | of the frequency components Vfi as the vibration frequency F of the anchor 2 Means 35.
[0015]
The vibration sensor 33 is an acceleration sensor that outputs an analog vibration signal SV in accordance with, for example, a change over time of the vibration amplitude V generated in the anchor surplus length portion 5a. An example of the signal conversion means 34 is to input and digitally convert the output vibration signal SV of the vibration sensor 33, and for example, convert the vibration amplitude V into a plurality of frequency components Vfi by a fast Fourier transform (hereinafter referred to as FFT). It is a program that breaks down into FIG. 5 shows an example of the output result of the signal converter 34, and shows a case where the vibration amplitude V is decomposed into six frequency components Vf1 to Vf6. The dominant frequency detection means 35 compares the power spectrum amounts | Vfi | of the frequency components Vf1 to Vf6 output from the signal converter 34 with each other, and the frequency of the dominant component having the maximum power spectrum amount | Vfi | Is a program that outputs the frequency F4 of the frequency component Vf4 as the vibration frequency F. The frequency F of the dominant component having the maximum power spectral amount | Vfi | corresponds to the inherent vibration frequency of the anchor 2 under the condition of the specific extra length L0 and the introduction load G. An example of the signal conversion means 34 and the dominant frequency detection means 35 is an FFT analyzer, but these may be included in the input means 42 which is a built-in program of the computer 36 of FIG. If the frequency component Vfi is simple, it is possible to directly detect the vibration frequency F from the output waveform of the signal converter 34 shown in FIG.
[0016]
In the storage means 37 of the load detection device 30, the relationship 38 between the vibration frequency F and the anchor introduction load G due to the impact of the anchor extra length 5a is experimentally obtained and stored. An example of the load detection means 40 of the load detection device 30 is that the measurement value of the vibration frequency F of the anchor by the frequency meter 32 is input via the input means 42, the relation 38 stored in the storage means 37 is read, and the vibration frequency F This is a program built in the computer 36 for detecting the anchor introduction load G based on the measured value and the relationship 38.
[0017]
Preferably, the storage means 37 is provided with a length measuring device 31 for storing the relationship 38 between the vibration frequency F and the introduction load G for each extra length L0 and measuring the extra length L0 of the head 5 of the anchor 2. The relationship between the measured value of the vibration frequency F by the frequency meter 32 by the load detecting means 40, the measured value of the surplus length L0 by the length measuring instrument 31, and the vibration frequency F and the introduced load G for each surplus length L0. 38, the introduction load G of the existing anchor 2 is detected. By storing the relationship 38 for each extra length L0, the introduction load G of the existing anchor 2 can be detected according to the extra length L0. However, if the surplus length L0 of the existing anchor 2 is known, it is sufficient if there is a relationship 38 between the vibration frequency F and the introduction load G corresponding to the known surplus length L0 when detecting the introduction load G. Therefore, the relationship 38 and the length measuring device 31 for each extra length L0 are not essential to the present invention.
[0018]
FIG. 2 shows an example of a flowchart of a method for detecting the introduction load of the existing anchor 2 using the detection device 30 of FIG. The introduction load detection method of the present invention will be described below with reference to the flowchart. First, at step 201, using the same reference anchor 46 as the existing anchor 2, a relationship 38 between the vibration frequency F and the introduction load G due to the impact of the extra anchor length 5a is experimentally obtained. For example, the anchor 2 before fixing on the ground can be used as the reference anchor 46.
[0019]
Details of step 201 are shown in the flowchart of FIG. Step 301 in FIG. 3 shows that a reference anchor 46 as shown in FIG. 4 is manufactured by using an anchor having the same material, structure, size, etc. as the existing anchor 2. The reference anchor 46 in FIG. 4 allows the tension member 4 to penetrate horizontally through the reaction wall 47, and causes the anchor head 5 to protrude on one side of the reaction wall 47 by the same length as the extra length of the existing anchor 2. The anchor body 3 is projected on the opposite side of the reaction force wall 47 and coupled to the hydraulic jack 48 by the coupler 22. The protruding anchor head 5 is attached to the reaction force wall 47 by the same method as the existing anchor 2, for example, by tightening the nut 6. The horizontal outward load applied to the anchor body 3 by the hydraulic jack 48 corresponds to the anchor introduction load G. In addition, the code | symbol 49 of FIG. 4 shows the steel square block for work safety to which the sandbag 50 was attached.
[0020]
In step 303, the load G of the hydraulic jack 48 is measured, and in step 304, the probe 32a of the frequency meter 32 of FIG. 1 is connected to the surplus length portion 5a of the anchor head 5, and the vibration frequency F due to the impact of the surplus length portion 5a is determined. Measure with frequency meter 32. Further, steps 303 and 304 are repeated as many times as necessary while changing the load G of the hydraulic jack 48 (step 305). The measured values of the jack load G and the vibration frequency F measured in steps 303 and 304 are input to the computer, and the relationship detection means 41 (see FIG. 4) which is a program built in the computer 36 is used as shown in FIG. A graph of the relationship 38 between the vibration frequency F and the introduction load G can be created. The graph shows the relationship 38 when the extra length L0 is fixed at 210 mm, and shows that the vibration frequency F increases as the introduction load G increases if the extra length L0 is constant.
[0021]
Preferably, the reference anchor 46 is used to obtain a graph of the relationship 38 between the vibration frequency F and the introduced load G at different extra lengths L0. In this case, in step 302, the extra length L0 of the anchor head 5 is measured by the length measuring device 31 of FIG. An example of the length measuring device 31 is a scale or a distance sensor for measuring the distance from the washer of the nut 6 to the upper end of the anchor head 5 shown in FIG. 9, but other suitable length measuring devices belonging to the prior art. Can be used. The measurement value of the extra length L0 by the length measuring device 31 is input to the computer 36 via the input means 42. For example, by repeating steps 302 to 305 a required number of times while changing the extra length L0 by adjusting the tightening of the nut 6, a graph of the relationship 38 between the vibration frequency F and the introduced load G for each extra length L0 is obtained. (Step 306).
[0022]
FIGS. 6B and 6C are graphs showing the relationship 38 between the vibration frequency F and the introduction load G when the extra length L0 is 230 mm and 250 mm. In creating the graph, the jack load G was changed in the same manner as in the graph creation in FIG. From the comparison of the three graphs in FIGS. 9A to 9C, it can be seen that if the introduction load G is constant, the vibration frequency F decreases as the surplus length L0 increases. The graph of the relationship 38 created by repeating steps 302 to 306 is stored in the storage means 37 of the computer 36 (step 307).
[0023]
Returning to FIG. 2 again, after step 201 is completed, the vibration frequency F at the time of striking the extra length portion 5a of the existing anchor 2 is measured by the frequency meter 32 at the site of measurement management or the like (step 203). If necessary, the extra length L0 of the existing anchor 2 is measured by the length measuring device 31 (step 202). Step 204 is a step of inputting the measured value of the vibration frequency F (and the extra length L0 if necessary) of the existing anchor 2 to the load detecting means 40 via the input means 42 and storing the vibration stored in the storage means 37. The relationship 38 between the frequency F and the introduced load G is read into the load detection means 40, and the existing anchor is determined by the load detection means 40 based on the input value of the vibration frequency F (and the extra length L0 if necessary) and the relation 38. 2 shows a process of detecting the introduction load G of 2.
[0024]
Specifically, if the input value of the extra length L0 of the existing anchor 2 is 210 mm, 230 mm, or 250 mm, the relationship between the input value of the vibration frequency F and the experimentally obtained FIGS. 6A to 6C. The introduction load G of the existing anchor 2 can be detected by obtaining the intersection with the 38 graph. Further, even when the relationship 38 between the vibration frequency F and the introduction load G corresponding to the input value of the extra length L0 is not experimentally obtained, the relationship 38 is obtained for each extra length L0. In this case, it is possible to detect the introduction load G of the existing anchor 2 by an interpolation method or an extrapolation method according to the input values of the extra length L0 and the vibration frequency F as will be described later.
[0025]
Step 205 in FIG. 2 shows a process of determining whether or not the detected load G of the existing anchor 2 is normal. For example, when the required load is not introduced, the tension of the nut 6 is re-tensioned at step 206 or the like. Take measures. The introduced load G and the determination result detected as necessary can be stored in the storage means 37 and output to the display 43a and the printer 43b. However, the present invention only needs to measure the anchor introduction load G, and steps 205 to 206 are not essential to the present invention. Then, when measuring the introduction load G of the other existing anchor 2, it returns to step 202 and repeats steps 202-206 mentioned above (step 207). When the material, structure, size, etc. of the existing anchor 2 are all the same, the relationship 38 between the vibration frequency F and the introduction load G stored in the storage means 36 can be used, and therefore it is not necessary to repeat step 201. .
[0026]
The introduction load detection device 30 of the present invention can be made portable, and the introduction load G of the existing anchor 2 can be detected by a simple operation of placing with a hammer 45 or the like. The complicated setup / operation at the site is not required, and the detection work of the introduction load G can be simplified and speeded up. In addition, anyone can easily detect the introduction load G of the existing anchor 2 without requiring any special skill. Moreover, since it is a non-destructive inspection, there is no possibility of causing a safety problem.
[0027]
Thus, provision of the “method and apparatus for detecting the loading of an anchor by a simple nondestructive inspection”, which is an object of the present invention, is achieved.
[0028]
【Example】
In step 307 of FIG. 3, the relationship 38 between the vibration frequency F and the introduced load G for each extra length L0 as shown in FIG. 6 is determined according to the introduced load G on the two-dimensional coordinates as shown in FIG. A curve group (hereinafter also referred to as an introduced load detection reference curve 39) of the relationship between the surplus length L0 and the vibration frequency F is shown. By expressing the relationship 38 between the vibration frequency F and the introduction load G as the reference curve 39 for detection of the introduction load, the relationship between the vibration frequency F and the introduction load G corresponding to the measured value of the extra length L0 of the existing anchor 2 is obtained. Even if it is not obtained experimentally, by plotting the measured values of the extra length L0 and vibration frequency F of the existing anchor 2 on the two-dimensional coordinates of FIG. 7, the extra length L0 and vibration are plotted. The introduction load G corresponding to the frequency F can be easily detected.
[0029]
The introduction load detection reference curve 39 shown in FIG. 7 includes three curves when the introduction load G is 500 kN, 750 kN, and 1000 kN. When the extra length L0 and the measurement value coordinates of the vibration frequency F of the existing anchor 2 plotted on the two-dimensional coordinates in FIG. 7 overlap with any curve, the anchor introduction load G can be detected immediately. Further, if the extra length L0 of the anchor head 5 is constant, the vibration frequency F increases as the introduction load G increases. Therefore, if the plotted measurement value coordinates do not overlap any curve, the measurement value The introduction load G of the existing anchor 2 can be estimated from the introduction loads G of two curves adjacent to each other with the coordinates therebetween.
[0030]
Specifically, on the two adjacent curves, the measurement value of the vibration frequency F (or surplus length L0) and the corresponding surplus length L0 (or vibration frequency F) corresponding to the measured value are obtained, and the two curves are introduced. From the load G, the introduction load G of the existing anchor 2 is detected by an interpolation method or an extrapolation method according to the measured value of the extra length L0 (or vibration frequency F). The introduction load detection reference curve 39 can naturally include three or more curves, and the detection accuracy of the introduction load G of the existing anchor 2 is improved by setting the interval between the introduction loads G of the curves to a necessary and sufficient size. It is possible.
[0031]
【The invention's effect】
As described above, the anchor introduction load detection method, apparatus, and program according to the present invention measure the surplus length of the existing anchor and the vibration frequency at the time of striking the surplus portion, and determine the surplus length and vibration frequency. Since the introduction load of the existing anchor is detected on the basis of the measured value and the relationship between the vibration frequency and the introduction load obtained experimentally, the following remarkable effects are obtained.
[0032]
(A) Since a large-scale measuring device as in the prior art is not required and the anchor introduction load can be detected by a portable detection device, the measurement management work can be facilitated.
(B) Since the introduction load can be detected by a simple operation such as connecting a detection device to an existing anchor, the measurement management work can be speeded up as compared with the prior art.
(C) Since no special skill is required for the detection work, anyone can easily detect the loading of the existing anchor.
(D) Since this is a non-destructive inspection, there is no risk of safety problems.
(E) If the relationship between the vibration frequency and the introduction load is experimentally sufficiently developed, the anchor introduction load can be detected with high accuracy.
(F) Since the anchor introduction load can be detected using a computer, it is possible to facilitate the recording and management of the detected data, and to prevent human errors in the management of the anchor recording.
(G) Expected to contribute to automation of anchor measurement management.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of the apparatus of the present invention.
FIG. 2 is an example of a flowchart of the method of the present invention.
FIG. 3 is an example of a flowchart of a method for creating a relationship between vibration frequency and introduced load.
FIG. 4 is an explanatory diagram of an experimental apparatus for obtaining a relationship between a vibration frequency and an introduction load.
FIG. 5 is an explanatory diagram of a method for obtaining a vibration frequency.
FIG. 6 is an example of a graph showing a relationship between a vibration frequency and an introduction load.
FIG. 7 is another example of a graph showing the relationship between vibration frequency and introduced load.
FIG. 8 is an explanatory diagram of a construction procedure of a ground anchor.
FIG. 9 is an explanatory diagram of an example of a conventional ground anchor structure.
FIG. 10 is an explanatory diagram of a conventional method for detecting an anchor introduction load.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ground 1a ... Stable ground 2 ... Anchor 3 ... Anchor body 4 ... Tensile material 5 ... Anchor head 6 ... Nut 7 ... Ground structure 8 ... Anchor hole 9 ... Anchor cap
10… Anchor plate 11… Coating material
13 ... Hole drilling machine
14 ... Case pipe or drill pipe
15 ... Injection hose 16 ... Grout material
18… Pressure head
19 ... Spacer 20 ... Hydraulic jack
21 ... Load cell 22 ... Coupler
23… Displacement meter 24… Fixed beam
25… Displacement meter 26… Fixed beam
28 ... Fixing body 29 ... Slide pipe
30 ... Introductory load detector 31 ... Length measuring instrument
32 ... Frequency meter 33 ... Vibration sensor
34 ... Signal conversion means 35 ... Predominant frequency extraction means
36 ... Computer 37 ... Storage means
38 ... Function (Relationship graph)
39… Introduction load detection reference curve
40 ... Load detection means 41 ... Relation detection means
42 ... Input means 43a ... Display
43b ... Printer 44 ... Keyboard
45… Hammer 46… Reference anchor
47 ... Reaction wall 48 ... Hydraulic jack
49 ... Steel block 50 ... Sandbag F ... Vibration frequency G ... Introduced load V ... Vibration amplitude SV ... Analog vibration signal
Vfi ... Frequency component | Vfi | ... Power spectrum amount of frequency component

Claims

The same reference anchor as the existing anchor in the method of detecting the anchor introduction load introduced by the locking / tensioning of the lower part to the ground structure by a known length from the head end of the anchor with the lower part fixed to the ground experimentally obtained relation between the vibration frequency and the introduction loads occurring excess length portion by striking extra length portion of the anchor head of the known length with anchor head Ri by the extra length portion striking the existing anchor detection method for measuring the vibration frequency arising in extra length portion, the vibration frequency of the measured value and the vibration frequency and detecting anchor introduced load comprising introducing load of existing anchor based on the relationship and between deployment load.

The detection method according to claim 1, wherein the relationship between the vibration frequency and the introduced load is determined by hitting the extra length of the reference anchor while applying a different load to the lower part of the reference anchor holding the extra extra length . A method for detecting an anchor introduction load obtained by measuring a vibration frequency generated in an extra length portion .

3. The detection method according to claim 1, wherein the vibration frequency is a power spectrum among a plurality of frequency components obtained by Fourier transform of a change over time in vibration amplitude generated in the extra length portion of the anchor head due to the extra portion hitting. A method for detecting the anchor introduction load that is the frequency of the dominant component with the largest amount.

In the detection method in any one of Claim 1 to 3, the relationship between the said vibration frequency and an introduction load is calculated | required according to surplus length, the surplus length length of the existing anchor is measured, and the said vibration frequency and surplus length length are measured. An anchor introduction load detection method that detects an introduction load of an existing anchor based on a measured value and the relationship between the vibration frequency and the introduction load.

5. The detection method of anchor introduction load according to claim 4, wherein the relationship between the vibration frequency and the introduction load for each extra length is a group of curves representing the relationship between the extra length and the vibration frequency for each introduction load. .

In the device that detects the anchor introduction load introduced by locking and tensioning the ground structure in the lower part from the end of the anchor head with the lower part fixed to the ground, the extra length of the existing anchor frequency meter for measuring the vibration frequency which occurs elongated portion of the anchor head by blow arising in the known by Ri excess length portion elongated portion striking of the length of the anchor head of the same reference anchor and the existing anchor vibration Storage means for storing the relationship between the frequency and the introduction load, and load detection means for detecting the introduction load of the existing anchor based on the measured value of the vibration frequency by the frequency meter and the relation between the vibration frequency and the introduction load. An anchor introduction load detection device.

7. The detection device according to claim 6, wherein a vibration sensor for detachably connecting to the surplus length portion of the anchor head and detecting a change with time of vibration amplitude caused by striking the surplus length portion, and the vibration amplitude are connected to the frequency meter. Signal converting means for decomposing into a plurality of frequency components by Fourier transform; and a dominant frequency detecting means for obtaining the frequency of the dominant component having the maximum power spectrum amount among the frequency components as the vibration frequency generated in the extra length of the anchor head ; An anchor introduction load detection device comprising:

In the detection method according to claim 6 or 7, a length measuring device for measuring the extra length of the existing anchor head is provided, and the relationship between the vibration frequency and the introduced load is stored in the storage means by extra length, Based on the measurement value of the vibration frequency by the frequency meter by the load detection means, the measurement value of the surplus length by the length measuring instrument, and the relationship between the vibration frequency by the surplus length and the introduced load, An anchor introduction load detection device that detects an introduction load.

9. The detection apparatus for anchor introduction load according to claim 8, wherein the relationship between the vibration frequency and the introduction load for each extra length is a group of curves representing the relation between the extra length and the vibration frequency for each introduction load. .

A computer to detect an anchor introduced load introduced by the locking-tension the lower the head end of the anchor that is fixed to the ground to the ground structure just extra length lower portion of known length, existing anchor same as storage means for storing the known length of the vibration frequency arising in due Ri excess length portion elongated portion striking of the anchor head of the reference anchor and the relationship between the introduction load, the anchor head by blow extra length portion of the existing anchor An input means for inputting the vibration frequency generated in the surplus portion of the part , and an anchor that functions as a load detection means for detecting the introduction load of the existing anchor based on the input value of the vibration frequency and the relationship between the vibration frequency and the introduction load Introductory load detection program.

11. The program according to claim 10, wherein the input means includes signal conversion means for decomposing a temporal change in vibration amplitude generated in the extra length portion of the anchor head by the extra length portion hitting into a plurality of frequency components by Fourier transform, and the frequency. An anchor introduction load detection program including a dominant frequency detection means for obtaining a frequency of a dominant component having the maximum power spectrum amount among components as a vibration frequency generated in the extra length portion of the anchor head .

The program according to claim 10 or 11, wherein the storage means stores the relationship between the vibration frequency and the introduced load for each extra length, inputs the extra length of the existing anchor by the input means, and the load detection means. An anchor introduction load detection program for detecting an introduction load of an existing anchor based on an input value of the vibration frequency and a surplus length and a relation between the vibration frequency and the introduction load for each extra length.

13. The program for detecting an anchor introduction load according to claim 12, wherein the relationship between the vibration frequency and the introduction load for each extra length is a group of curves representing the relationship between the extra length and the vibration frequency for each introduction load.